COCCIDIA 419 



A. eherthi (Labbe) (Fig. 190). Schizogony in Portunus depura- 

 tor and sporogony in Sepia officinalis. Spores (a) germinate in the 

 crab gut, each hberating 3 sporozoites (6) which grow and produce 

 merozoites (lO/z by 2^) by schizogony in peri-intestinal connec- 

 tive tissue cells (6 chromosomes) (c-/) ; when host crab is eaten by 

 a cuttlefish, merozoites penetrate gut wall and develop into mi- 

 cro- and macro-gametocytes (h, k), and further into gametes. 

 (j-l); anisogamy (m) produces zygotes; zygote nucleus contains 

 12 chromosomes which become divided into 2 groups of 6 at first 

 division {n, o); repeated nuclear division (p) forms many sporo- 

 blasts (q), each transforms itself into a spherical spore with 3 

 sporozoites (Dobell, Naville and Belaf). 



Genus Merocystis Dakin. Sporogony in kidney of the whelk, 

 Buccinum; schizogony unknown in another host (possibly a crab) ; 

 microgametocytes produce first cytomeres which in turn form 

 microgametes; anisogamy gives rise to zygotes, zygote forms 

 many sporoblasts, each developing into a spore; spore spherical, 

 with 2 sporozoites. One species. 



M. kathae D. (Fig. 191, a, h). In kidney of Buccinum undatum; 

 spores spherical, about 14/i in diameter. 



Genus Pseudoklossia Leger et Duboscq. Anisogamy and spo- 

 rogony in kidney of marine mussels; oocyst or zygote produces 

 numerous spores; spore with 2 sporozoites ; no residual body; schi- 

 zogony unknown, in another host. 



P. pectinis L. et D. (Fig. 191, c). In kidney of Pecten maximus 

 in France; association of 2 sporozoites 3.5m in diameter. 



Genus Caryotropha Siedlecki. Both schizogony and sporogony 

 take place in a host. One species. 



C. mesnili S. In coelom (floating bundles of spermatogonia) of 

 the polychaete, Polymnia nebulosa; schizogony in bundle of sper- 

 matogonia, in which cytomeres with 10-16 nuclei are formed and 

 then merozoites; schizogony repeated; gametocytes undergo de- 

 velopment also in the same host cells; macrogametes become set 

 free in coelom, where union with microgametes takes place; each 

 oocyst forms about 16 spores, spore with usually 12 sporozoites; 

 cysts are extruded with reproductive cells of host worm. 



Genus Myriospora Lermantoff. Anisogamy and sporogony in 

 marine snails; schizogony unknown; oocyst forms numerous 

 spores, each with 2 sporozoites. One species. 



M. trophoniae L. In the cardiac body of polychaete, Trophonia 



